The present invention generally relates to injection molding machines, and more particularly, to an injection molding machine having a detector where a storage medium is installed.
In an injection molding machine, resin heated and melted in a heating cylinder is injected into a cavity of a mold apparatus under high pressure so that the cavity is filled with the molten resin. The molten resin is then cooled and solidified so as to obtain a molded article.
Because of this, a plurality of driving parts and driven parts are provided in the injection molding machine. In addition, detectors are provided for the driving parts and driven parts so as to detect a driven state of the driven parts such as speed or positions of the driven parts.
For example, in an electric injection molding machine, a plurality of motors such as a servo motor for injection, a servo motor for screw rotating, a servo motor for mold clamping, and others, are provided as the driving parts. Furthermore, a screw, a cross head and others are provided as the driven parts. Rotation detectors, such as rotary encoders, are provided for output shafts of these servo motors. For example, the rotation detector recognizes a number of rotations and an amount of rotation of the servo motor and outputs a detection signal representing the recognized number of rotations and the recognized amount of rotation of the servo motor. The detection signal is used as a signal for detecting the speed and the position of the driven part that is driven by the output shaft of the servo motor. In a case where speed control for the driven part is implemented, the controller receives the driven signal from the rotation detector. The controller controls the number of rotations and the amount of rotation of the servo motor based on the speed represented by the detection signal. That is, the controller controls the number of rotations and the amount of rotation of the servo motor so as to make the driven part have a designated speed.
FIG. 1 is a block diagram schematically showing a feed back control system of a servo motor of a conventional electric injection molding machine. This block diagram shows minimum structural elements in order to simplify the explanation of the feed back control system. However, an actual feed back control system has a more complex structure than the block diagram.
Referring to FIG. 1, a rotation detector 22 is provided at an output shaft 25 of a servo motor 21. A detection signal from the rotation detector 22 is input to a controller 20 through an interface circuit 23. The detection signal from the rotation detector 22 is converted to a signal suitable for a digital process at the controller 20 by the interface circuit 23. The controller 20 controls the number of the rotations and the amount of the rotation of the servo motor 21, based on information with regard to the number of the rotations and the amount of the rotation of the servo motor 21 that is detected by the rotation detector 22.
Meanwhile, in a case where the rotation detector 22 is provided at the output shaft 25 of the servo motor 21, it is necessary to measure an original point of the servo motor 21 and store the original point as original point position information. This is because it is necessary to recognize the number of the rotations and the amount of the rotation of the servo motor 21 by using the original point as a standard so as to control the number of the rotations and the amount of the rotation of the servo motor 21.
Furthermore, detector information, in addition to the original point position information of the servo motor 21, is stored in order to distinguish the rotation detector 22. The detector information is defined as individual information to distinguish the rotation detector uniquely. Information represented by a numerical value or a character such as from the alphabet, for example xe2x80x9ca model of the rotation detectorxe2x80x9d, xe2x80x9ca serial numberxe2x80x9d, xe2x80x9ca version numberxe2x80x9d or the like, is applicable to the detector information. The injection molding machine has one controller 20. Generally, the controller 20 controls a plurality of the servo motors of the injection molding machine in parallel. Hence, a plurality of the detection signals are input from the rotation detector to the controller 20. In this case, it is necessary to distinguish from which rotation detector the detection signal is input. In addition, it is necessary to distinguish whether or not the input detection signal is from a proper rotation detector.
Thus, in the conventional electric injection molding machine, the original point position information of the servo motor 21 is combined with the detector information regarding the rotation detector 22 provided at the output shaft 25 of the servo motor 21, and stored in a memory 26 installed in the controller 20 after the rotation detector 22 is provided for the servo motor 21. In a case where a memory is installed in the interface circuit 23, the original point position information of the servo motor 21 and the detector information are stored in the memory.
However, in the above mentioned conventional injection molding machine, it is necessary to implement an operation for detection of the original point position of the injection molding machine and store the original point position information of the servo motor 21 and the detector information of the rotation detector 22 in the memory 26, again, whenever the rotation detector 22 is exchanged. In this case, for example, if a setting operation to input the information of the original point position after the rotation detector is exchanged is missed or if the injection molding machine where an improper rotation detector is provided at the servo motor 21 in error is operated, the injection molding machine works incorrectly.
Furthermore, in the above mentioned conventional injection molding machine, the original point position information of the servo motor 21 and the detector information of the rotation detector 22 has to be stored, whenever the interface circuit 23 having the original point position information and the detector information or the controller 20 is exchanged, or the rotation detector 22 and the interface circuit 23 having the original point position information and the detector information or the controller 20 are exchanged. Hence, operation for exchanging the interface circuit 23, the controller 20, or the servo motor 21 is complicated. As a result of this, human support for maintenance is required inconveniently, whenever the interface circuit 23, the controller 20, or the servo motor 21 is exchanged.
Accordingly, it is a general object of the present invention is to provide a novel and useful injection molding machine having a detector where a storage medium is installed.
Another and more specific object of the present invention is to provide an injection molding machine, including a driving part, a driven part driven by the driving part, and a detector detecting a driven state of the driven part, wherein a storage medium is installed in the detector.
The storage medium may be a one chip microcomputer. The one chip microcomputer is suitable as the recording medium since the one chip microcomputer has a memory and is distributed at a low price.
Detector information or molding machine information to distinguish the detector may be stored in the storage medium. The detector information may include the model of the detector, a serial number, or a version number, of the detector. The molding machine information may include information with regard to a serial number of the injection molding machine and a driving apparatus. The molding machine information may further include information with regard to a plasticizing capacity or mold clamping force. The driving part may be a motor. The detector may be provided at an output shaft of the motor. The driving part may be operated by supplying hydraulic pressure. The injection molding machine may further include a driving transmission part for transmitting motive force by the driving part to the driven part, wherein the detector is provided at the driving transmission part. The detector may be provided at the driving part or the driven part. The detector may detect a rotation, a position or a speed of the driven part.
It is another object of the present invention is to provide an injection molding machine, including a driving part, a driven part driven by the driving part, a detector detecting a driven state of the driven part and outputting a detection signal, and a controller receiving the detection signal so as to control motive force by the driving part, wherein a storage medium is installed in the detector, a memory is stored in the controller, and common information is stored in the storage medium and the memory.
Since common information is stored in the storage medium and the memory of the controller, in a case where the detector is exchanged, an interface circuit or the controller is exchanged, or the detector and the interface circuit or the controller is exchanged, it is possible to compare and rewrite the common information. Accordingly, it is possible to easily exchange the detector, the interface circuit or the controller, so that an operator himself can exchange them easily so as to prevent the injection molding machine from working incorrectly. That is, the maintenance of the injection molding machine is easy so that the injection molding machine restarts working easily after the exchanging process is finished.
For example, the original point position information of the driving part and the molding machine information to distinguish the injection molding machine may be stored in the storage medium of the detector where the detector information to distinguish the detector has already been stored, and the original point position information of the driving part and the detector information to distinguish the detector may be stored in the memory of the controller where the molding machine information has already been stored.
According to the above mentioned invention, it is possible to store the same detector information and the same original point position information in the controller and compare the detector information and the original point position information. Hence, it is possible to prevent the injection molding machine from working incorrectly due to missing a setting operation after the rotation detector is exchanged. Furthermore, since the molding machine information, in addition to the detector information and the original point position information, is stored in the recording medium and the controller, it is possible the positively distinguish between a case where only the controller is exchanged and a case where both the rotation detector and the controller are exchanged.
The controller may compare detector information stored in the storage medium and a detector information stored in the memory so as to report the detector information stored in the storage medium is different from the detector information stored in the memory. Furthermore, the controller may compare original point position information stored in the storage medium and original point position information stored in the memory so as to report the original point position information stored in the storage medium is different from the original point position information stored in the memory.
Based on the report of that the original point position information stored in the storage medium is different from the original point position information stored in the memory, a correct setting operation is prompted for before the injection molding machine is driven. Because of this, working the injection molding machine incorrectly due to missing a setting operation after the detector is exchanged, is prevented.
The controller compares molding machine information stored in the storage medium and molding machine information stored in the memory so as to report the molding machine information stored in the storage medium is different from the molding machine information stored in the memory.
Based on the report of that the molding machine information stored in the storage medium is different from the molding machine information stored in the memory, it is possible to determine a case where the rotation detector and the controller are exchanged simultaneously. In a case where only the controller is exchanged, the controller can read the original point position information stored in the storage medium. Hence, it is not necessary to detect the original point position and implement a setting operation again.